For such problems as long time for supplying oxygen, large consumption of oxygen and high consumption of steels occurred in steelmaking by the 100 t converter in General Steelmaking Plant of Angang Steel Co., Ltd., the old parameters for oxygen lance nozzles were optimized, including the nozzle throat diameter, outlet diameter, dip angle of center and height control of lances. The optimized results show that the oxygen supply time was shortened by about100 s, the consumption of oxygen was reduced by 1.81 m3 per tone molten steel and the content of phosphorus in molten steel at the end point of converter was reduced by 0.01%, spot blowing times was reduced so that iron and steel materials consumption was reduced.